The Sources of International Law

This new edition of Hugh Thirlway's authoritative text provides an introduction to one of the fundamental questions of the discipline: what is, and what is not, a source of international law. Traditionally, treaties between states and state practice were seen as the primary means with which to create international law. However, more recent developments have recognized customary international law, alongside international treaties and instruments, as a key foundation upon which international law is built. This book provides an insightful inquiry into all the recognized, or asserted, sources of international law. It investigates the impact of ethical principles on the creation of international law; whether 'soft law' norms come into being through the same sources as binding international law; and whether jus cogens norms, and those involving rights and obligations erga omnes have a unique place in the creation of international legal norms. It studies the notion of 'general principles of